Diamond drill bit



-Dec.2, 1941. LjHAvucK 2,264,440

DIAMOND DRILL BI-T ,Fi eduiu 1, 1940 Inventor JsssE L ffAvL/cK,

A #omey Patented Dec. 2, 1941 UNITED STATE DIAMOND 1mm. BIT Jesse L. Havlick, Spokane, Wash.

Application July 1, 1940, Serial No. 343,473

3 Claims.

I The presentrinvention relates to a diamond abrasive drilling bit designed for drilling holes for blasting or grouting work where no core is required. In the construction of drill bits heretofore \made for such purposes, the drill bit usually forms a very small core, or no core at all. Those bits which product a small core possess the objectionable feature of plugging or clogging the tiny center core hole. In other types of bits which made no core at all no cutting action was produced at the center point of the bit because of lack of peripheral speed in the center.

It is accordingly an object of the present invention to provide a diamond abrasive drill bit of this character which will provide a greater cutting area at the center point where there is usually a lack of peripheral speed and in addition, to provide an area within which an increased number of cutting points may be placed than was heretofore possible.

A further object is to providea drill bit of this character having an inwardly extending coneshaped center portion and providing a radially extending slotted opening which communicates with the apex of the cone to provide a water passage for circulating water through the bit to carry away the heat and cuttings made by the bit and also to prevent the formation of any core which is larger than the width of said slot.

A further object is to provide a device of this character of simple and practical construction, which is eificient and reliable in performance, relatively inexpensive to manufacture and otherwise well adapted for the purpose for which the same islntended.

Other objects and advantages reside in the details of construction as more fully hereinafter described and claimed, reference being had to the accompanying drawing forming part hereof, wherein like numerals refer to like parts throughout, and in which: I

Figure 1 is a top plan view.

Figure 2 is a side elevational view, and

Figures 3 and 4 are longitudinal sectional views 7 taken respectively on the lines 33 and 44- of Figure 1.

Referring now to the drawing in detail. the numeral 5 designates the bit stock which'is internally threaded as shown at 6 at its inner end for attaching to the shank of the tool, (not shown). The outer end of the stock is closed and formed with a reduced shoulder I on which is fitted the cap 8 which may be secured in position thereon in any suitable manner, preferably by providing lateral openings 4 in the reduced-portion of the stock and a central opening 3 in the end of the stock for receiving a portion of the cap material as shown at 8 when the cap is cast on the stock. a a

The outer end of the cap is formed with an in wardly extending conical recess 9. The edge of the cap is rounded as shown at it. The cap 8 is preferably constructed of case metal in order that the chip diamonds I I may be embedded in the outer surface thereof to firmly anchor the diamonds in position. The diamonds are positioned in the surface of the cone recess 9 as well as over the rounded edge I0 and partly over the outer surface of the cap.

A pair of radially extending grooves l2-'-l2 are formed in the rounded edge portion in of the cap, at diametrically opposite sides thereof, the grooves extending downwardly along the outer wall of the cap and terminating at their inner ends within the recess 9 in spaced relation from each other, as more clearly shown in Figure 1 of the drawing. The centerof the cap is formed with a radially extending slotted opening l3 which extends across the apex of the cone-shaped recess 9 and communicates at' each end with the grooves i2l2, the. slotted opening extending entirely through the cap for receiving water from the interior of the stock. At each end of the opening I3 is a longitudinally extending opening M which communicates with the hollow interior of the stock, as shown in Figure 3.

By reason of the cone-shaped recess 9 a greater number of the diamonds ll may be mounted at the central portion of the cap and the lack of peripheral speed at the center of the bit is reduced to a minimum. Accordingly, a bit is produced which practically eliminates the formation of a'core at the center of the bit. The groove 12 serves to distribute water from the slotted opening I3 and the openings it to the outer sides of the cap.

It is believed the details of construction, ad-

vantages and manner of use of the tool will be readily understood from the foregoing without further detailed explanation.

Having thus described the invention, what I claim is:

1. A drill bit comprising a hollow bit stock.

- conical recess in the outer end of the cap having its base axially disposed, diamond chips embedded in the recess and outer edge of the cap and exposed in the surface thereof, and a pair of grooves extending radially in the outer edge of the cap at diametrically opposite sides and having their inner ends spaced apart at the base of the recess, said recess having an opening connecting said grooves and communicating with the interior of the stock.

2. A drill bit comprising a hollow bit stock having a reduced outer end provided with radial and axial openings, said axial opening communieating with the interior of the stock, a cap cast on the reduced end of the stock and haviim portions thereof anchored in said openings, a conical recess in the outer end of the. cap having an opening communicating with the interior of the stock, abrasive elements embedded in the surface oi the cap and in the surface of the recess, a water passage in the cap communicating with the interior oithe stock and a radial water dismunicating radial and axial openings, said axial opening communicating with the interior of the stock, a cap cast on the reduced end of the stock and having portions thereof anchored in and closing said openings, a conical recess inthe outer end of the cap having an opening communicating with the interior of the stock, abrasive elements embedded in the surface of the cap and in the surface of the recess, said recess having a slot providing a water passage communicating with the interior of the stock, longitudinally extending water passages at the ends of the slot and a radially extending water distributing channel in the outer surface of the cap communicating with said slot and also with said longitudinal passages.

JESSE L. HAVLICK. 

